ARM: 7772/1: Fix missing flush_kernel_dcache_page() for noMMU

Commit 1bc39742

 (ARM: 7755/1: handle user space mapped pages in
flush_kernel_dcache_page) moved the implementation of
flush_kernel_dcache_page() into mm/flush.c but did not implement it
on noMMU ARM.

Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
Cc: <stable@vger.kernel.org> # 3.2+: 1bc39742

: ARM: 7755/1
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>